Department of Physical Medicine and Rehabilitation, National Yang-Ming University Hospital, I-Lan, Taiwan.
J Surg Res. 2012 Jul;176(1):108-13. doi: 10.1016/j.jss.2011.09.027. Epub 2011 Oct 11.
Our previous study showed that preconditioned local somatothermal stimulation (LSTS) protected subsequent ischemia-reperfusion injury of the skeletal muscle. The exact mechanisms of LSTS preconditioning remain unknown. The aim of this study was to test the hypothesis stating that heat stimulation induces free radical production, increases enzymatic scavenging activity, and subsequently enhances the expression of heat shock protein 70 (HSP-70) in skeletal muscles.
After LSTS was applied onto the left quarter ventral abdomen muscle of male Sprague-Dawley rats, the underling muscles were collected at the intervals of baseline, 5-, 15-, 30-, and 60-min after LSTS. The time-dependent profiles of free radical production and enzymatic scavenging activity were measured. The influence of nitric oxide (NO) on HSP-70 expression was evaluated by pretreatment of an NO synthase inhibitor.
The concentrations of reactive oxygen species, NO metabolites, and malondialdehyde increased significantly 5 min after LSTS, whereas the scavenging activity reduced to the lowest level 5 min (dismutase) and 15 min (catalase and glutathione) after LSTS. Expression of HSP-70 was significantly lower in the LSTS with NO synthase inhibitor group than in the LSTS group.
LSTS induces oxidative stress and the scavenging response in the underlying skeletal muscle, which might explain the possible mechanisms of LSTS preconditioning-induced muscle plasticity.
我们之前的研究表明，局部体感热刺激（LSTS）预处理可保护随后的骨骼肌缺血再灌注损伤。LSTS 预处理的确切机制尚不清楚。本研究旨在验证以下假说，即热刺激可诱导自由基产生、增加酶的清除活性，进而增强骨骼肌中热休克蛋白 70（HSP-70）的表达。
在雄性 Sprague-Dawley 大鼠的左季腹前区肌肉施加 LSTS 后，在 LSTS 后即刻、5 分钟、15 分钟、30 分钟和 60 分钟时采集下腹部肌肉。测量自由基产生和酶清除活性的时间依赖性特征。通过预先给予一氧化氮合酶抑制剂，评估一氧化氮（NO）对 HSP-70 表达的影响。
LSTS 后 5 分钟，活性氧、NO 代谢物和丙二醛的浓度显著增加，而清除活性在 LSTS 后 5 分钟（超氧化物歧化酶）和 15 分钟（过氧化氢酶和谷胱甘肽）降至最低水平。在给予一氧化氮合酶抑制剂的 LSTS 组中，HSP-70 的表达明显低于 LSTS 组。
LSTS 可诱导下腹部骨骼肌的氧化应激和清除反应，这可能解释了 LSTS 预处理诱导肌肉可塑性的可能机制。
